Automatic expansion-valve for refrigerating apparatus.



No. 630,6l7. Patented Aug. 8, 1899.

A. T. MARSHALL. AUTOMATIC EXPANSION VALVE FOR REFRIGERATING APPARATUS.(Application filed Feb. 11, 1898.) (No Model.)

Witnesses. w J M I nventor.

(I. 5 Attorneys.

UNITED STATES PATENT QOF IC ALBERT T. MARSHALL, OF BROCKTON,MASSACHUSETTS.

AUTOMATIC EXPANSION-VALVE FOR REFRlGE RATING A PPA RATUS.

srncrrrca'rron forming partof Letters Patent No. 630,617, dated Augusta, 1899. Application filed February 11, 1898. Serial No. 669,895. (Nomodel.)

To all-whom, it may concern:

Be it known that I, ALBERT T. MARSHALL, a citizen of the United States,residing at Brockton,in the county of Plymouth and State ofMassachusetts, have invented a new and useful Automatic Expansion-Valvefor Re-' frigeratingApparatus, of which the following is aspecification.

My invention relates to a regulator for antomatically controlling theflow of the refrigerating medium in the pipes of a refrigeratingapparatus; and the object of my invention is to provide. a strong,simple, inexpensive, and durable regulator for automatically controllingthe flow of the refrigerating medium, so as to produce the greatestpossible efficiency of the apparatus in connection with which the sameis employed.

To these ends my invention consists of the parts and combinations ofparts,'as hereinafter described, and more particularly pointed out inthe claims at the end of this specification.

In the accompanying drawings, Figure 1 is a sectional view of anautomatic expansionvalve for refrigerating apparatus constructed Figs. 2to 6, in-.

according to my invention. elusive, are detail perspective views ofparts thereof; and Fig. 7 is a diagrammatic view of a refrigeratingapparatus provided with an automatic regulator constructed according tomy invention.

A refrigerating apparatus employing anhydrous ammonia or similarrefrigerating mediums ordinarily comprises a pump or compressor, a,storage-chamber for the condensed liquid refrigerating medium, andexpansion pipes or coils in which the refrigerating medium is allowed toexpand into the form of vapor. The admission of the refrigerating mediumto the expansion-coils is controlled ordinarily by a small needle-valve,which is termed the expansion-valve.

The efficiency and economy attained in refrigerating apparatus depend onthe adj ustment of the expansion-valve. sion-valve is openedsufliciently to allow a. quantity of refrigerating medium to enter theexpansion-coils greater than can be exhausted \or taken care of bythepnmp, the expansion medium will pass through the pump while still inthe form of a liquid, and as the cool- If the expaning or refrigeratingaction depends upon the vaporlzation of the refrigerating medium anexcessive feed of the refrigerating medium will allow the brine tank orcompartment being refrigerated to become gradually warmer, even Whilethe compressor or pump is working under its full capacity. 0n the othersion-coils being inoperative, while at the same. time the compressor orpump will be work-.

ing against a comparatively high vacuum.

To obtain the best resultsffrom any given refrigerating apparatus,it isessential that the expansion-valve should be set so that all of therefrigerating medium fed into the expansion-coils should be just equalto the capacity of the compressor or pump-that isto say,

the quantity of liquid fed-t0 -the expansioncoils should not besufficiently great to allow any of it to pass to the compressor in theform of a liquid, while at the same time it should tion is therefore toprov'ideaan expansionvalve for refrigcratingapparatus having anadjustable resistance or spring-pressure normally tending to keep-thesame closed and which is also acted uponv by the pressure of the.refrigerating mediunrin the circulating-- pipes opposed by athermostatic pressure.

be sufficient to allow vaporization to take place throughout the entireexpansion-coil.

The especial object of my present inven- To accomplish this purpose, thepreferred form of my automatic regulator for refrigerating apparatuscomprises a two-part casing, a flexible diaphragm secu red in placebetween the parts thereof, a valve-stem extending from one side of thediaphragm, and a slotted tube extending fromlthe opposite side of thediaphragm and having a coiled spring normally tendingto close the valve,the tension of which may be adjusted by an adju'stingscrew extending tothe outside of the casing,

the features of novelty of said automatic regulator being, moreparticularly pointed out in the claims at the end of this specifica- Ition. A thermostatic pipe or chamberis connected to one of the parts ofthe two-part casing, and a quantity of the refrigerating medium can beadmitted to and confined in the thermostatic pipe through avalve-controlled by-pass formed entirely within the casing.

Referring to the refrigerating apparatus illustrated diagramaticall y inFig. 7, A designates a receptacle for the condensed or liquidrefrigerating medium, from which the same passes through acirculating-pipe to the automatic regulator R, thence through acirculating-pipe 11 to the expansion-coil 12. The vaporizedrefrigerating medium is pumped from the expansion-coil12 by a pump orcompressor P and is passed through a condensing-coil 13, which may becooled by a water-jacket in the ordinary manner, condensing therefrigerating medium back into a liquid and returning the same to therecep tacle A.

The automatic regulator R, as illustrated in Fig. 1, comprises a casingformed by the castings 14 and 15, which are clamped together by bolts17, so as to secure a flexible diaphragm 16 in place between saidcastings.

On the under side of the diaphragm is a disk 18, having a threadedspindle extending up.

through the diaphragm. A nut or washer 19 is threaded onto the spindleof the disklS, and also threaded onto the spindle of the disk 18, so asto form a check-nut for the collar 19, is a slotted tube 20. Coiledaround the slotted tube 20 is a spring 21, which is con fined at itsupper end byacollar22. Mounted inside of the slotted tube 20 is a nut24, having arms which extend through the slots in the tube 22 to supporta washer 23, which engages the lower end of the coiled spring 21. Asshown most clearly in Figs. 1 and 5, the nut 24 is slabbed or cut awayon diagonally opposite sides, so that it can be readily introduced intothe tube 20 in position to have its arms extend through the slotsthereof.

An adjusting-screw 25 is threaded into the nut 21 and extends up througha stuffing-box to the outside of the casing, the upper end of' the boltbeing squared, so that it can be readily turned or adjusted by asuitable handle or wrench when desired.

Adjustably threaded into the disk 18, on the under side of the diaphragm16, is the expansion -valve stem 26. The valve-stein 26 carries a valve35, cooperating with a valveseat 36. At its lower end, below the valve,

" the stem 26 is squared or made polygonal and engages a correspondingsocket in a locking-sleeve 28, .said sleeve being held from turning bymeans of a pin 29 and being supported in place by a cap 31. Athermostatic receptacle or pipe 30 is connected to the up per casting 14of the casing, and, as most clearly shown in Fig. '7, the thermostaticpipe is preferably carried through the brine tank or compartment beingrefrigerated by the expansion-coil 12, so as to be exposed to exactlythe same temperature to which the expansioncoil is exposed.

A quantity of the anhydrous ammonia or other refrigerating medium can beadmitted to the upper part of the casing of the regulator and to thethermostatic pipe 30 through a by-pass 31, controlled by a valve 32. Theby-pass 31 is located entirely within the castings forming the casing ofthe regulator and extends up through the diaphragm 16.

In order to prevent the by-pass 31 from being closed by the compressionof the diaphragm 16 when the clamping-bolts 17am tightened, I preferablyprovide a small bushing 33, located in a socket in the casting 14, asshown in Fig. 1.

In adjusting and operating my regulator as thus constructed theadjusting-screw 25 may be turned so as to bring its nut 24 to the bottomof the slot in the tube 20 to positively open the expansion-valve, thusallowing an unrestricted flow of the refrigerating medium through thecirculating-pipes 10 and 11. The valve 32 may then be opened to admit aquantity of the expansion medium to the upper part of the casing of theregulator and the thermostatic pipe 30. In the use of my automaticregulator it is ess'entialto provide some means for positively holdingthe expansionvalve open. Otherwise the system could not be readilycharged, and pressure being first introduced on the underside of thediaphragm would not be resisted by a thermostatic pressure and theexpansion-valve wonld be held closed, thus obstructing the properoperation The valve 82 is then closed, an'das the thermostatic pipe 30is exposed to the same temperature as the expansion-coil 12 the pressurein the expansion-coil will exactly balance the thermostatic pressure.The pump or compressor is then started and the adjustingscrew 25 isturned to raise its nut 24 and place the coiled spring 21 under tension,tending to close the expansion-valve. By means of this construction itwill be seen that the ggormal pressure in the expansion-coil will beexactly balanced by the thermostatic pressure independently of thechanges in temperature in the brine or compartment being refrigerated.The suction or vacuum caused by the pump normally tends to open theexpansion-valve and is balanced or resisted by the tension of the spring21.

To obtain the best results, the regulator is' usually set so that as therefrigerating medium leaves the expansion-coils it has all just turnedto vapor. This can be determined by observing the frosting of thecirculating-pipes connected with the expansion-coils. For example, ifthe circulating-pipe frosts only at the outlet end of the expansion-coilit shows that an unnecessarily large quantity of expansion medium isbeing fed, and the tension of the regulating-spring 21 should beincreased. On the other hand, it' too small a once to be overcome by thepump will be sub- 4 quantity of the refrigerating medium is being fedtheoutlet end of the expansion-coil will remain comparatively warm evenafter the apparatus has assumed its normal working conditions, and thetension of the spring substantially equal to the capacity of the pump,the regulator will not thereafter need to be adjusted, and the'changesin the temperature of the brine or compartment being refrigerated willnot altect the proper feed of the refrigerating medium-that is to say,as the brine cools the pressure of the refrigerating medium in .theexpansion-coils and the thermostatic pressure will fall or be reducedsimultaneously, so that these pressures will always balance each otheraudthe resiststantially a constant.

Whenever it is'desired to positively close the expansion-valve, so as toentirely stop the refrigerating action, the ad justing-screw may beturned to raise the nut to the upper end of the slots in its'tube or tobring the convolutions of the spring into engagement with each other. v

A further advantage in the specific construction which I haveillustrated resides in the fact that byremoving the lower cap 34 andlocking-sleeve 28 the expansion-valve stem can be readily unscrewed andtaken out to be cleaned or trued up.

I am aware that changes may be made in my automatic regulator forrefrigerating apparatus without departing from the scope of my inventionas expressed in the claims. I

do not wish, therefore, to be limited to the form that I have shown anddescribed; but, What I do claim, and desire to secure by Letters Patentof the United States, is-

1. In an automatic refrigerating apparatus, the combination ofthe'expansion-coil, and an automatic regulator comprising a diaphragmmountedin a closed casing so' as at all times to be'acted upon on oneside by the pressure of the refrigerating medium in the expansioncoil,and on the other side by a thermostatic pressure, an expansion-valvearranged to be operated by the diaphragm, a coiled springmounted withinthecasing, and an adj ustin-grod extending to the outside of the casingand connected so that it may be used to positivelyopen theexpansion-valve, or may be used to adjust the tension of the coiledspring, so that the expansion-valve will automatically open at any"desired difference between the thermostatic pressure and the pressureof the refrigerating medium, substantially as described.

2'. In an automatic regulator for refrigerating apparatus, thecombination of a casing formed by castings 14 and 15,, a diaphragm 16interposed between said castings, clampingbolts 17 for securing theparts together, so that the diaphragm may be acted uponon one side by athermostatic pressure, and on the other side by the pressure of therefrigerating medium,anexpansion-valve 35 arranged tobe operated by thediaphragm, a disk'lS having a threaded stud extending through thediaphragm, a collar 19 threaded on said stud, a

slotted tube 20 threaded onto the stud and pansion-valve willautomatically open at any desired diiference between the thermostaticpressure and the pressure of the expansion medium, substantially asdescribed.

3. In an automatic regulatorforrefrigerating apparatus, the combinationof a two-part casing, a diaphragm therein, circulatingpipes for therefrigerating apparatus connected' to one part of the casing, anexpansion- 'valve stem adjustably connected to the diaphragm, athermostatic pipe opening into the other part of the casing, avalve-controlled by-pass formed entirely in said casing for and mittingand confining a quantity of the refrigerating medium in the thermostaticpipe, a spring normally tending to hold the expansion-valve closed, andmeans for adjusting the tension of the spring to allow theexpansion-valve to open at any desired difierence between the pressurein the circulating-pipes and thermostatic pipe, substantially asdescribed.

4. In an automatic regulator for ice-machines, the combination of atwo=part casing, a diaphragm interposed between the'parts of saidcasing, clamping-bolts for securing the parts of the casing together,circulatingpipes connecting to one part of the casing, a thermostaticpipe connected to the other part of the casing, said casing having avalvecontrolled by-pass formed therein and extending through thediaphragm, and a bushing for preventing the diaphragm from closing theby-pass when the clamping-bolts are tightadj usting-screw 25 threadedinto not 24, an expension-valve stem threaded into the disk 18, a.locking-bushing 29 having a squared socket for engaging a correspondingportion of the valve-stem 26 to hold the same from turning, and athermostatic pipe or chamber 30 opening into the upper part of thecasing, said casing being formed with a valve-controlled by-pass 31 foradmitting the refrigerating medium to theupper part of the casing andthe thermostatic pipe 30, substantially as de- 10 scribed.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

ALBERT '1. MARSHALL.

l \Vitnesses:

PHILIP W. SOUTHGATE. LOUIS W. Sou'rmm'm.

